How Do Covariant, Contravariant, and Mixed Tensors Transform?

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The transformation laws for covariant and contravariant tensors are defined by their respective basis vectors and how they relate to changes in coordinates. The metric tensor field is expressed as g = g_{ab} dx^a dx^b, while a tangent vector field is represented as v = v^a ∂/∂x^a. Understanding these transformations requires applying the chain rule to relate the differentials dx^a and the partial derivatives ∂/∂x^a across coordinate changes. This foundational knowledge is crucial for working with mixed tensors in mathematical physics.

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What are the transformation laws of covariant and contravariant tensors? Also, how do I deal with mixed tensors in terms of transformations and in representation?
 
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Well, if you actually put the basis (co)vectors in, rather than just looking at coordinates, it's clear what the transformation laws should be. For example, the metric tensor field is computed from its coordinates as

[tex]g = g_{ab} dx^a dx^b[/tex]

whereas a tangent vector field would be something like

[tex]v = v^a \frac{\partial}{\partial x^a}[/tex]

And since you (presumably) know, by the chain rule, how to relate [itex]dx^a[/itex] and [itex]\partial / \partial x^a[/itex] with [itex]d\bar{x}^a[/itex] and [itex]\partial / \partial \bar{x}^a[/itex]...


(I'm assuming you're talking about changes-of-coordinates. If you mean something else, please elaborate!)
 

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